Relative time scale analysis for pressure propagation during ignition process of a scramjet

The supersonic combustion ramjet (scramjet) engine is expected to become the most efficient air breathing propulsion system in the hypersonic flight regime. The behavior of wall pressures propagation was examined using a direct-connect model scramjet experiment along with high-frequency pressure measurements. High-frequency pressure transducers are employed to record the history of pressure response during ignition process. A first order plus dead time (FOPDT) model is employed to model the S-shape step response curve. The time scale distributions of pressure propagation are reported in this paper. The characteristics of pressure propagation are closely related to the combustion mode of the scramjet.